The utility model relates to a valve guide hole centering, using air floatation rapid adjusting positioning, tool rod free-swings or spindle set free oscillation, a level and stepless speed regulation of vertical engine cylinder head valve seat machining machine tool maintenance, purpose is to make sure that the roundness and valve seat ring seal cone taper requirement, and can ensure that the valve seat seal cone and valve guide hole center line of the circle Dynamic requirements. Its structure are mainly lathe bed, boring head, specific, boring tool rod, cutting tools, locating mandrel and pneumatic components, boring head including rigid boring head and spindle sleeve guide bush universal swing boring head, boring cutter bar including rigid tool rod and universal tool rod, can translational or rotational workpiece relative bed mesa, artifacts can also around two mutually vertical and parallel to […]